The only prior chemical investigations of bryozoa appear to be (1) our initial report that certain bryozoa such as Bugula neritina contain anticancer constituents (Pettit, G. R.; J. F. Day, J. L. Hartwell, H. B. Wood, Nature, 1970, 227: 962-963); (2) a preliminary study of an adrenochrome-like pigment in the same species (Villela, G. G. Proc. Soc. Exptl. Biol. Med. 1948, 68: 531-553); and (3) isolation of the indoles flustramines A and B from Flustra foliacea (Carle', J. S.; Christopherson, C., J. Org. Chem. 1980, 45: 1586-1589; Carle', J. S.; Christopherson, C., J. Org. Chem. 1981, 46: 3440-3448). Of the presently known cyclic ionophores, only the Streptomyces griseus component aplasmomycin seems distantly related to bryostatin 1. (Okami, Y.; Okazaki, T.; Kitahara, T.; Umezawa, H.; J. Antibiot. 1976, 29: 1019; and Nakamura, H.; Iitaka, Y.; Kitahaa, T.; Okazaki, T.; Okami, Y., J. Antibiot. 1977, 3.0: 714).
Financial assistance was provided by Contract N01-CM-97262 with the Division of Cancer Treatment, NCI, National Institutes of Health, DHW, Grant Nos. CA16049-01 through 07 awarded by the National Cancer Institute, DHW, Mrs. Mary Dell Pritzlaff, the Olin Foundation (Spencer T. and Ann W.), the Fannie E. Rippel Foundation, Mrs. Eleanor W. Libby, the David Ware Waddell Foundation, Mrs. Pearl Spear, and Mr. Robert B. Dalton. For other very helpful assistance we are pleased to thank Drs. J. D. Douros, J. J. Einck, D. Gust, R. R. Inners, L. W. Knapp, P. Lohavanijaya, M. I. Suffness, J. M. Schmidt, J. Witschel, Jr., Mr. M. A. Carlson, Miss B. L. Norfleet, Miss K. M. Welch, the Smithsonian Institution Oceanographic Sorting Center, and the National Science Foundation Regional Facility at the University of South Carolina (CH78-18723). We also acknowledge support provided by NIH CA24487 (JC), and the National Science Foundation.